Especially considering the Cingular Wireless commercial that I have been laughing at for the last couple months about the Player being traded for himself because I thought it was improbable.

That's hilarious Ed.

The most notable player to have suffered this ignominy is Harry Chiti. Note that Chiti's transaction history on RetroSheet (via Baseball-Reference) don't list any transactions for Chiti after the first leg of his self-swap...this implies the return trip was as a minor leaguer, which makes the phenomenon much more common.

Edit: Clarification - Chiti was originally sold by Cleveland to the Mets, not traded. He was subsequently returned to the Indians to complete a previous PTBNL commitment. So he wasn't "traded" for himself.

It also happened (more or less) to Dickie Noles and Mark Ross. Technically neither of these players were traded for themselves...they were moved in "conditional deals" which can result in a player being returned to his original team after a 30 day period because some aspect of the deal couldn't be finalized.

Vic Power is sometimes included in this category, but technically he wasn't traded for himself in 1964. He was traded for another PTBNL and then was later re-purchased by his original team (the Angels).

Edit: typo